灌溉与旱作条件下长期施肥塿土剖面磷的分布和移动

Phosphorus distribution and leaching in loessial soil profile with long-term fertilization under irrigation and rainfed condition

利用12年长期定位试验研究了灌溉和旱作条件下不同施肥处理对土土壤剖面全磷与有效磷(Olsen-P)分布和移动的影响。结果表明,土施磷后主要累积在耕层,极大地提高了0—20cm土层全磷与Olsen-P含量。旱作条件下,施用磷肥或化肥配施有机肥提高了100cm以上土体全磷与Olsen-P含量;而化肥配合有机肥,Olsen-P含量在100—300cm土壤剖面中都高于对照(不施肥)和化肥处理。灌溉条件下,与旱作有相同趋势,但磷钾、有机肥配施氮磷钾处理,全磷和Olsen-P不仅在0—300cm剖面中高于对照和氮磷钾处理,而且也高于旱作条件下的相同处理。土上存在磷素的淋失。

The distribution of total P and Olsen P in loessial soil profile were studied using the 12 years long term fertilization experiments under rain fed and irrigation conditions(The National Monitoring Base of Soil Fertility and Fertilizer Efficiency of Loessial Soil). The result indicate that phosphorus from fertilizer mainly accumulated in plow layer of loessial soil, the contents of soil total and Olsen P in top 20cm soil layer as well as that in soil profile are increased greatly by fertilization; Under rainfed condition, soil total P and Olsen P of soil layer above 100cm were increased by applying phosphate or phosphate combined with organic manure. The Olsen P content of MNPK in 100—300cm soil profile were higher than that of CK, PK and NPK treatments, and the same trends also showed under irrigation condition. The total P and Olsen P contents of PK,MNPK treatments in 0—300cm soil profile were not only higher than that of CK and NPK, but also higher than that of same treatments under rainfed condition. Phosphorus losses by leaching do exist in lossial soil.